11,606 reputation
11049
bio website vyznev.net
location Helsinki, Finland
age
visits member for 2 years, 11 months
seen 4 hours ago

I'm a PhD student in biomathematics, working on stochastic individual-based models of evolution in spatially structured populations. My other interests include cryptography, programming games and puzzles, photography and graphic design.

I started programming (in AmigaBASIC) when I was 10 years old. Nowadays, I'm most comfortable using Perl, C and JavaScript. I know Java and PHP too, but I can't really say I like them. I also know some Python, but not as much as I'd like.


CC-Zero Please consider any (original) code I post to Stack Overflow and other Stack Exchange sites to be released under CC-Zero unless stated otherwise. You may do whatever you want with it and don't have to credit me in any way, although of course that would be nice.


I'm the main author and maintainer of the Stack Overflow Unofficial Patch (SOUP), a user script for browsers with GreaseMonkey-compatible user script support (Firefox, Chrome, Opera, possibly Safari) that fixes or works around a number of outstanding issues with the Stack Exchange user interface.

I tend to answer a lot more questions than I ask. Some answers I'm rather proud of:


Jul
25
answered How random is the shared secret in the Diffie Hellman key agreement
Jul
25
answered Sending TLS messages with out encryption using openssl code
Jul
24
revised Ed25519 choice of private key implementation
added 349 characters in body; edited tags
Jul
24
answered Ed25519 choice of private key implementation
Jul
20
answered Is HMAC-MD5 considered secure?
Jul
18
reviewed Approve suggested edit on Send a message to an entire group of recipients
Jul
18
comment using random encrypted RSA challenge as key material
The output of HKDF-Expand is uniquely determined by its parameters (PRK, info, length). Thus, if you want to derive multiple independent keys from the same PRK using HKDF, you need to either 1) use a different info parameter for each, or 2) generate them all with one call to HKDF-Expand and split the output. Generally, just appending a counter to the info string will work fine. (Ps. See also my edit to the answer.)
Jul
18
revised using random encrypted RSA challenge as key material
added 645 characters in body
Jul
18
answered using random encrypted RSA challenge as key material
Jul
18
comment Secret sharing scheme with possibility to change the secret
If the encryption method used is secure, it should not be vulnerable to known-plaintext attacks.
Jul
18
revised Secret sharing scheme with possibility to change the secret
texify; add tag
Jul
18
revised Secret sharing scheme with possibility to change the secret
added 659 characters in body
Jul
18
revised Secret sharing scheme with possibility to change the secret
edited tags; clarified that each share alone (together with P) should be enough to reconstruct the secret
Jul
18
answered Secret sharing scheme with possibility to change the secret
Jul
6
reviewed Reject suggested edit on Cryptographic Challenge: How to Say Something Confidentially to Snowden?
Jul
6
reviewed Reject suggested edit on How to efficiently generate a stream of independent, but biased random bits?
Jul
3
answered Is it possible to insert a key derivation function when using EAX?
Jul
1
comment Designing a protocol to record attendance to lectures
The teacher can see the students in the classroom when he's teaching, right? So he cannot gain any information by looking at the pictures that he couldn't gain equally well just by looking at the students himself (and having a good memory for faces). And you implied that was acceptable above.
Jul
1
comment Designing a protocol to record attendance to lectures
On a disk? Or a USB stick, if you prefer. Why is that a problem, anyway? Disk space is cheap nowadays. Or is there some hidden requirement here? In any case, I don't think most modern face recognition programs actually store images of the faces (unless told to do so e.g. for review purposes), but only relatively compact abstract representations of the facial features of the subject.
Jul
1
revised Are stream ciphers no longer considered by NIST?
major copyedit